1. Field
This disclosure relates generally to micro electro-mechanical systems (MEMS), and more specifically, to shielding for a MEMS device and method therefor.
2. Related Art
Micro electro-mechanical systems (MEMS) components are increasingly being used in a wide variety of applications, especially where the demand for miniaturized structures is called for. Typically, a MEMS component is a miniaturized device having a movable structure suspended from a substrate, and associated circuitry that both senses movement of the suspended structure and delivers the sensed movement data to one or more external devices for processing. MEMS devices can be implemented as accelerometers to selectively deploy air bags in automobiles, as gyroscopes to detect rotation rates in airplanes, as microphones to convert audible signals to electrical signals, and so forth. The use of MEMS microphones, rather than conventional condenser microphones, has come to be appreciated for their small package profile and compatibility with surface mount techniques and automated pick-and-place equipment.
MEMS components are typically fabricated on semiconductor wafers. A MEMS component may be fabricated in or on a semiconductor wafer using standard integrated circuit fabrication equipment. Once the wafer is processed, it is diced to form individual die. Each singulated die is packaged, and the MEMS component may be inserted into a socket or bonded to a non-semiconductor substrate, such as a printed circuit board (PCB) as part of an overall system.
In some applications, shielding is used to isolate radio frequency (RF), electrostatic noise, and electro-magnetic interference (EMI) from the MEMS device. Typically, a metalized cover is fitted over the MEMS device for this purpose. In the case of a MEMS microphone, an acoustic hole in the cover allows sound in.
MEMS fabrication and packaging can have a significant impact on the ability of such MEMS components to penetrate cost-sensitive markets, such as the cellular telephone industry. For example, the metalized cover over the MEMS microphone increases both the size and cost of the device.
Therefore, what is needed is a MEMS device that solves the above problems.